Ensuring the Reliability of Underground Cable Systems

March 16, 2022

Hydro-Quebec implements a multilevel partial discharge detection approach on its medium-voltage underground cable systems.

Medium-voltage underground cable systems are a critical part of the electric distribution network. Like any other power apparatus, the insulation of these underground cable systems ages over time. For example, many underground cross-linked polyethylene (XLPE) cables were installed in North America in the 1970s and 1980s, with a reported design life in the range of 30 years to 40 years. Nowadays, utilities are faced with underground distribution systems that are, theoretically, either at the end or past their design life.

Diagnostic tests assess power system asset health

The replacement of every piece of equipment and accessory that has reached its theoretical design service life is not an option for both economical and practical reasons. Therefore, maintenance and diagnostic tests are common practice to assess the health of critical power system assets. This can be challenging for utilities when workers or funding are not available to test every electrical component periodically.

Partial discharge is a common cause of deterioration

The power distribution team at Canadian utility company Hydro-Quebec recently found that most in-service failures in its underground distribution network occurred at cable joints. A common cause of deterioration in these cable accessories was partial discharges (PD).

Therefore, Hydro-Quebec Distribution implemented a thorough inspection procedure to decrease the rate of failure in its underground distribution network. Among other tools, a multilevel PD detection approach was adopted to minimize the need for expertise on-site.

Find out more in our Paper

OMICRON application engineer Mathieu Lachance and Hydro-Québec Distribution engineers Michel Trépanier, Claude Tremblay and Lionel Reynaud have teamed up to write a recent article for T&D World Magazine. They describe how PD measurements have enabled Hydro-Quebec to detect dielectric anomalies on not only aging underground accessories but also those newly installed in the network. Several case examples highlight the advantages of such the multilevel PD detection approach for the underground cable system.

Read the article3.60 MB

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